Download MS-PowerPoint

INTRODUCTION TO
PSYCHOLOGY
Chapter 3
The Brain and the Nervous
System
Car racer
Zimbardo
At the end of this Chapter
you should be able to:
• Understand the structure of the brain
and the nervous system
• Learn about modular organisation of
the brain
• Learn the methods used to study the
brain
The Nervous System
 Nervous System
 the body’s speedy, electrochemical
communication system
 consists of all the nerve cells of the
peripheral and central nervous systems.
 It has two parts;
 Central Nervous System (CNS)
 Peripheral Nervous System (PNS)
Nervous
system
Central
(brain and
spinal cord)
Peripheral
Autonomic (controls
self-regulated action of
internal organs and glands)
Somatic (controls
voluntary movements of
skeletal muscles)
Sympathetic
(arousing)
Parasympathetic
(calming)
Central Nervous System
 Central Nervous System (CNS)
 Controls the brain and spinal cord
– The Brain—directs mental processes and
maintains basic life functions
– The Spinal Cord—receives sensory
input, sends information to the brain,
responds with motor output
How the Nervous System is
Studied
Field: NEUROSCIENCE
Study of: nature, functions, origins of
the nervous system:
multidisciplinary;
Begins with studying cells of the
nervous system
Studying the Nervous
System
• Clinical observation
– Phineas Gage: frontal
lobe damage
• Neuropsychology
– what happens to behavior
when brain structures are
damaged
• Experimental techniques
– Lesioning brain structures, observing
consequences
– Transcranial magnetic stimulation:
temporary loss of brain function in
isolated areas near surface of brain (just
under scalp)
Neuroimaging techniques:
To examine structures and functioning of
brain
Computerized Tomography (CT):
- Images created from multiple x-ray
images of brain.
+ good image quality
- only show structure
Neuroimaging techniques, cont’d..
Magnetic resonance imaging (MRI),
Functional MRI (fMRI):
- A non-invasive procedure that produces a
two-dimensional view of an internal organ
or structure, especially the brain and spinal
cord. (MRI)
- create pictures of brain structure;
- Can examine behavior of brain in “real
time” (fMRI).
+ high spatial resolution,
+ shows function
- low temporal resolution
Neuroimaging techniques, cont’d..
Electroencephalography (EEG):
- Detects electrical current at surface of brain
(scalp)
- Wave forms/patterns vary with brain activity
+ high temporal resolution, shows function
- low spatial resolution (does not show where in
the brain the activity is taking place)
Brain Structure
Hindbrain
– Controls many functions key to survival,
including keeping airway clear, heart
beat, breathing, reflexes, sleep,
respiration, balance
Midbrain
– Coordinates motion, relays information to
other sites; targeting auditory and visual
stimuli, regulating body temperature
Forebrain
– Cortical and sub-cortical structures;
intelligent adaptive behavior.
Brain Structure
Cortex
• 3 mm. thick
• 80% of total brain volume
• Convoluted (folded, wrinkled)
structure enables more tissue to fit
• The cortex provides flexibility in
behavior
• Divided into 2 hemispheres and 4
paired lobes: frontal, temporal,
occipital, parietal
Cortex
Cortex
• Localization:
– each structure has a somewhat
different set of tasks and skills
• Multiple structures needed to
perform complex tasks
The Brain’s Higher Functions
• The Cerebral Cortex —the bumpy,
convoluted area on the outside of the
two cerebral hemispheres that
regulates most complex behavior,
including receiving sensations, motor
control and higher mental processes
(i.e., thinking, personality, emotion,
memory, motivation, creativity, selfawareness, reasoning, etc.)
Cerebral Cortex—Four
Lobes
• Frontal Lobes—receive and
coordinate messages from other lobes
as well as motor control, speech and
higher functions
• Parietal Lobes—receives information
about pressure, pain, touch and
temperature
Cerebral Cortex—Four
Lobes
• Temporal Lobes—hearing, language
comprehension, memory and some
emotional control
• Occipital Lobes—vision and visual
perception
Lateralization
• The Cerebral Cortex is divided into
two hemispheres (left and right)
connected by the Corpus Collosum
• Each hemisphere receives and sends
information to the opposite side of the
body
• Each hemisphere also specializes in
certain functions
Lateralization
LEFT and Right tightly coordinated -Both necessary for
efficient and normal brain function
Each hemisphere has some
special abilities:
LEFT :
sophisticated
language, inferences
Right : facial recognition,
pattern recognition
The Left Hemisphere (or Left
Brain)
• Language Functions (speaking, reading,
writing, and understanding language)
• Analytical Functions (mathematics,
physical sciences)
• Right-hand touch
The Right Hemisphere (or
Right Brain)
• Non-verbal abilities (music, art,
perceptual and spatial manipulation,
facial recognition)
• Some language comprehension
• Left-hand touch
The Cerebral Cortex
Broca’s Area
 an area of the left frontal lobe that directs
the muscle movements involved in
speech
 Wernicke’s Area
 an area of the left temporal lobe involved
in language comprehension and
expression
(speech production)
(speech comprehension)
Specialization and Integration
Specialization and Integration
• Brain activity when hearing, seeing, and
speaking words
Plasticity
• Definition: “Subject to alteration”
• Historically, nervous system deemed
NOT plastic
• New evidence: Neurons can change,
form new connections with other
neurons. As a result, the brain itself
can entirely change.
Should all psychological
questions have biological
answers?
• In many cases, a biological answer to a
sociological question:
– Not practical
– Not helpful
– Not possible!
• Many other levels of analysis need to be
applied in order to answer many questions
about human behavior